Connecting rods connect pistons to crankshafts of internal combustion piston engines. The connecting rods exhibit both rotating motion and reciprocal motion during their use. One connecting rod end, often referred to as the small end, is a reciprocating end that is representative of up and down motion. The other, opposite end, often referred to as the large end, is a bearing end, which rotates with movement of the crankshaft.
In many instances, an internal combustion engine may include a number of pistons and thus a corresponding number of connecting rods. It can be important for an automobile manufacturer to balance the connecting rods to within a predetermined weight of each other to reduce wear and noise. In connecting rod balancing, each end may be weighed independently given the rotational and reciprocal motion of the big and small ends.